Iris Apatow was 3 in Knocked Up when she played the character 'Charlotte'.
That was over 17 years ago in 2007.
This was her first recorded movie acting credit (although may not technically be her first actual acting role).
Today she is 21, and has starred in 7 movies in total, 6 of those since Knocked Up was released.
In Knocked Up, I think Iris Apatow looks: